Incompetence

I hired this company recently to close roof leakage and paid them 60% of R6000. their qoute stated that they replace perljne and roof sheets to do the job. When their workers came they painted the roof and replaced the perline. I waited thinking they were still coming for the real job only to be told that the job is complete and I must pay the balance, obviously I refused. Fortunately rain fell and the water came through the roof and I informed them. They insisted that they did more than the job by replacing nails, something I didn't ask for. I feel that this is represented itself because they don't have the expertise required. I asked them if they believed that the amount they charged me equalled what they did on my roof. Instead they insisted that I must pay the balance despite the fact that my roof is still leaking like before.